Why is Mars red?
Mars's soil and dust are rich in iron minerals that have rusted over billions of years. Fine dust blown into the thin atmosphere spreads that rusty color across the whole planet, which is why Mars glows reddish-orange in the night sky.
What's it like on Mars?
- Thin air: the atmosphere is mostly carbon dioxide and less than 1% as thick as Earth's. You couldn't breathe, and unprotected water would boil away.
- Freezing cold: the average temperature is about −60 °C (−80 °F).
- Giant dust storms: some grow big enough to cover the entire planet for weeks.
- Huge canyons: Valles Marineris stretches about 4,000 km, roughly the width of the United States.
- Ice: both poles have ice caps, and there's frozen water hidden under the surface.
Mars's two moons
Mars has two small, lumpy moons, Phobos and Deimos. They're only a few kilometers to about 22 km across, and they may be captured asteroids. Phobos is slowly spiraling inward toward Mars.
How do we explore Mars?
Mars is the most visited planet after Earth. Orbiters map it from above, while landers and rovers study rocks, weather and ancient water up close. NASA's Curiosity and Perseverance rovers have been exploring old lakebeds and river channels, searching for signs that tiny life may once have existed. Perseverance even carried Ingenuity, the first helicopter to fly on another planet.
Could people live on Mars?
Sending humans is one of the biggest goals in space exploration. Explorers would need protection from radiation and cold, a way to make water and oxygen from local ice, and food grown in sealed greenhouses. Missions to the Moon are the practice run for all of it.